1. Field of Endeavor
The present invention relates to a light diffusing system and more particularly to a system for diffusing light from an optical fiber or light guide.
2. State of Technology
U.S. Pat. No. 6,829,411 for a wide angle light diffusing optical fiber tip, by James C. Easley, patented Dec. 7, 2004, provides the following description: “A diffusing optical fiber tip yielding a homogenous output pattern having a total illumination angle of at least 180 degrees. The diffusing optical fiber tip has an outer diameter which is no greater than that of the optical fiber, and appears as a point source of illumination, having substantially the same output pattern when immersed in water as it does in air. The diffusing optical fiber tip is manufactured on the end of a typical acrylic optical fiber by causing longitudinal stresses in the fiber end, which are then relieved by forming axial cracks in the fiber core at the optical fiber tip. As a result, light exiting the optical fiber must traverse a scrambled pathway caused by a complex interaction of reflections and refractions, yielding wide angle diffuse illumination.”
U.S. Pat. No. 6,576,163 for a durable fiber optic diffuser tip and method of making same, by Steven H. Mersch, patented Jun. 10, 2003, provides the following description: “A method of manufacturing a medical instrument for diffusing light from an optical fiber is provided. The medical instrument includes an optical fiber having a proximal portion including a cladding layer surrounding the core and a distal portion having a diffuser tip comprising a protective coating made of acrylic or methylpentene surrounding the core, an optical coupling layer, and a sleeve. The protective coating strengthens the distal end of the optical fiber so that it can withstand a higher bending moment at failure than the uncladded core. At the same time, the protective layer has an index of refraction that is between the indices of refraction of the core and the optical coupling layer to direct light out of the core through to the optical coupling layer.”
U.S. Pat. No. 6,418,252 for a light-diffusing fiber optic chamber, by Duncan J. Maitland, patented Jul. 9, 2002, provides the following description: “A light diffusion system for transmitting light to a target area. The light is transmitted in a direction from a proximal end to a distal end by an optical fiber. A diffusing chamber is operatively connected to the optical fiber for transmitting the light from the proximal end to the distal end and transmitting said light to said target area. A plug is operatively connected to the diffusing chamber for increasing the light that is transmitted to the target area.”
U.S. Pat. No. 6,364,874 for a device for irradiating internal cavities of the body, by Bays et al, patented Apr. 2, 2002, provides the following description: “A device for the irradiation of internal cavities of the body includes a flexible catheter, made of a transparent material, containing a fiber optic of which the section at one end is designed to radially diffuse light coming from a source arranged at the other end. An inflatable balloon fixed to one end of the catheter surrounds the diffusing section of the fiber optic. The balloon is made of an elastomeric material that diffuses the light and is prefabricated by molding based on the shape of the cavity to be treated. The balloon presses against the cavity wall and, with the thickness of its surfaces remaining constant after inflation, the pressure needed for inflation is low and cannot damage the cavity tissues.”
U.S. Pat. No. 6,361,530 for a durable fiber optic diffuser tip and method of making same, by Steven H. Mersch, patented Mar. 26, 2002, provides the following description: “An medical instrument for diffusing light from an optical fiber is provided. The medical instrument includes an optical fiber having a proximal portion including a cladding layer surrounding the core and a distal portion having a diffuser tip comprising a protective coating made of acrylic or methylpentene surrounding the core, an optical coupling layer, and a sleeve. The protective coating strengthens the distal end of the optical fiber so that it can withstand a higher bending moment at failure than the uncladded core. At the same time, the protective layer has an index of refraction that is between the indices of refraction of the core and the optical coupling layer to direct light out of the core through to the optical coupling layer.”
U.S. Pat. No. 6,361,180 for a light diffusing apparatus using light guide, by Keiji Iimura, patented Mar. 26, 2002, provides the following description: “A light diffusing apparatus using light guide comprises at least first light guide portion for light leakage, second light guide portion solely for light transmission; and third light guide portion for an optical communication with first and second light guide portion. The first light guide portion has first end (or side surface) and second light guide portion has second end which is optically opposed to the first end. The third light guide portion forms substantially non-linear (or curved) cross-section and the first, second and third light guide portions form substantially a single-piece construction. At least a single transparent panel-like member (or, sheet-like, plate-like or film-like member) may be used for the first, second and third light guide portions. At least a ribbon-like optical fiber cable (i.e. tape-like or film-like optical fiber cable) may be used for the first, second and third light guide portions, having a plurality of optical fibers which are aligned in parallel each other. The light diffusing apparatus can output light with a desired predetermined distribution pattern of surface brightness i.e. luminance. The distribution pattern of output light may produce uniform i.e. even surface brightness i.e. luminance. Therefore, the light diffusing apparatus may be suitably used typically in surface light sources, photographic film viewers, backlights or front lights of passive displays such as liquid crystal displays, light indicators and vehicle lights, etc.”
U.S. Pat. No. 6,270,492 for a phototherapeutic apparatus with diffusive tip assembly, by Edward L. Sinofsky, patented Aug. 7, 2001, provides the following description: “An optical transmissive, light-diffusing, fiber tip assembly having a radiation-scattering particles incorporated therein and a reflective end surface is disclosed for use in phototherapy. As radiation propagates through the fiber tip, a portion of the radiation is scattered in a cylindrical (or partially cylindrical) pattern along the length of the fiber tip. Radiation which is not scattered during this initial pass through the tip is reflected by at least one surface of the assembly and returned through the tip. During this second pass, the remaining radiation (or at least a major portion of this returning radiation) again encounters the scatterers which provide further radial diffusion of the radiation. Preferably, the scattering medium and the reflective end cap interact to provide a substantially uniform axial distribution of laser radiation over the length of the tip apparatus. Methods and devices are also disclosed in which a dielectric structure is operatively coupled to phototherapeutic instrument to reflect light without substantial heating. The invention is particularly useful in light diffusive tip assemblies for phototherapy that have components which increase in temperature after prolonged exposure to light, such as mirrors and metallic structures incorporated into such diffusers to facilitate radiographic or fluoroscopic imaging during a therapeutic procedure.”
U.S. Pat. No. 6,004,315 for an optical fiber diffuser and method of making, by Michael G. Dumont, patented Dec. 21, 1999, provides the following description: “An optical fiber device includes a polymeric optical fiber having a proximal end for coupling to a source of light, and a diffusing region. The polymeric optical fiber includes a core and a cladding around the core. The diffusing region includes a length of the polymeric optical fiber in which the cladding is partially removed to expose the core and in which the exposed core and the remaining cladding have a roughened surface for outwardly diffusing light carried through the polymeric optical fiber. The diffusing region is preferably formed by abrasion, for example by directing a particle jet at the optical fiber while rotating and translating the optical fiber with respect to the particle jet. The particle jet may include microscopic glass beads which roughen the optical fiber core. The density of scattering sites may be varied along the length of the diffusing region to produce a desired light output pattern. The optical fiber device is useful in medical applications, including as a component of catheter or endoscopic systems.”
U.S. Pat. Nos. 5,754,717 and 5,946,441 for a light-diffusing device for an optical fiber, methods of producing and using same, and apparatus for diffusing light from an optical fiber, by Victor C. Esch, patented May 19, 1998, and Aug. 31, 1999, respectively, provide the following description: “A diffusing tip is provided for diffusing light from a light-emitting end of an optical fiber in a radial distribution pattern relative to the axis of the tip and along a length of the tip. The tip has an inner core and an outer covering which define a light guide. The outer covering is modified on its interior surface adjacent to the core such that light transmitted down the light guide is removed from the core upon encountering a surface modification on the interior surface. The light so removed is transmitted to the outer surface along the length of the tip, where it can be used to irradiate a selected object or material. The diffusing tip preferably provides light in a substantially uniform intensity distribution for the substantially uniform irradiation of a selected object or material.”
U.S. Pat. No. 5,908,415 for phototherapy methods and apparatus, by Edward L. Sinofsky, patented Jun. 1, 1999, provides the following description: “An optical transmissive fiber tip assembly having a radiation-scattering particles incorporated therein and a reflective end surface is disclosed for use in phototherapy. As radiation propagates through the fiber tip, a portion of the radiation is scattered in a cylindrical (or partially cylindrical) pattern along the length of the fiber tip. Radiation which is not scattered during this initial pass through the tip is reflected by at least one surface of the assembly and returned through the tip. During this second pass, the remaining radiation (or at least a major portion of this returning radiation) again encounters the scatterers which provide further radial diffusion of the radiation. In one embodiment, a diffusive tip assembly is disclosed for diffusing radiation from an optical fiber. The tip assembly is adapted to receive the distal end of said fiber in order to direct the radiation outward, and includes a light transmissive tube or housing aligned with the distal end of the fiber. The tube includes a reflective end cap and a light scattering medium disposed therein such that radiation propagating through said fiber enters the scattering medium and a portion of the radiation is scattered outward through said tube, and another portion passes through the scattering medium and is reflected by the end cap for retransmission through said scattering medium. Preferably, the scattering medium and the reflective end cap interact to provide a substantially uniform axial distribution of laser radiation over the length of the tip apparatus.”
U.S. Pat. No. 5,871,521 for a laser probe for medical treatment, by Kaneda et al, patented Feb. 16, 1999, provides the following description: “A medical laser probe to be used as a laser irradiation unit in laser treatment that is performed by irradiating a living body with laser light. The laser probe irradiates laser light uniformly, utilizing laser light effectively by concentration thereof, achieving limited irradiation of laser light and taking countermeasures against stains forming on the probe. The laser probe is provided with (1) a transparent light diffuser for radiating laser light received by a light-guide fiber in the direction along the longitudinal axis of the light diffuser and in radial directions from this axis to the peripheral side surface thereof and (2) a detachable protective diffusion tube for further diffusing laser light radiated from the transparent light diffuser. A reflector may be provided between the light diffuser and the diffusion tube. Further, shielding plates may be provided on the protective diffusion tube.”
U.S. Pat. No. 5,632,767 for loop diffusers for diffusion of optical radiation, by Edward L. Sinofsky, patented May 27, 1997, provides the following description: “Methods and apparatus are disclosed for diffusing radiation from a optical fiber to provide a larger exposure area for phototherapy and to provide a substantially uniform energy distribution to a major portion of the exposure area. The invention is especially useful in constructing and implementing circumferential and/or sideways-emitting diffusive tip assemblies, or quasi-spherical diffusive tip assemblies for optical fibers to direct laser radiation in a radially outward pattern relative to the fiber's axis. In one aspect of the invention, a plurality of optically-transmissive fiber tip assemblies are employed to act as diffusers. The two or more fiber tip assemblies are deployed as loops which create a uniform illumination pattern. By ‘looping’ or ‘folding’ the fibers, a plurality of fibers can be deployed in conjunction with one another to create geometric exposure patterns with increased energy density while still avoiding ‘hot spots.’”
U.S. Pat. No. 5,431,647 for a fiberoptic cylindrical diffuser, by Purcell, Jr. et al, patented Jul. 11, 1995, provides the following description: “A fiberoptic diffuser has an optical fiber having a light transmitting core, cladding about the core, and a buffer layer about the cladding. The core at the distal end portion of the fiber is exposed and a diffusing sleeve is disposed thereabout. A transparent cylindrical cap is disposed outwardly of the diffusing sleeve and overlies the exposed core, and a reflector is provided in the cap in axial alignment with the distal end of the core to reflect light rays exiting the core. The light rays exiting the core are reflected by the reflector and are refracted by the sleeve to exit through the cap over substantially the entire length of the exposed core.”
U.S. Pat. No. 5,429,635 for a fiberoptic spherical diffuser, by Purcell, Jr. et al, patented Jul. 4, 1995, provides the following description: “A fiberoptic diffuser for photodynamic therapy applications comprises an optical fiber having a light transmitting core, cladding about the core, and a buffer layer about the cladding. The distal end portion of the fiber core is free from the cladding and buffer layer, and the exposed distal end of the core has a conical configuration. A cap extends about the distal end portion of the fiber and has a spheroidal end portion of light diffusing material which extends about the exposed conical end of the fiber core. The cap also has a mounting portion engaged with the buffer layer of the fiber, and it provides a cavity in which the exposed core is disposed. Light rays passing through the fiber to its distal end are refracted outwardly at the conical end of the core into the spheroidal end portion of the cap and are further refracted by the cap to exit therefrom over substantially the entire surface of the spheroidal end portion.”
U.S. Pat. No. 5,363,458 for a fiber optic light diffuser, by Pan et al, patented Nov. 8, 1994, provides the following description: “Heat and light generating, fiber optic, cylindrical diffusers are structured to operate more efficiently and with increased uniformity by the inclusion of rings of prescribed indicies of refraction about the unclad distal end portion of the diffuser. Such a diffuser also includes a conical distal tip. A sealed Teflon™ sleeve containing diffusing material in place over the entire length of the diffuser also improves the uniformity of heat distribution.”
U.S. Pat. No. 5,344,419 for an apparatus and method for making a diffusing tip in a balloon catheter system, by James R. Spears, patented Sep. 6, 1994, provides the following description: “An apparatus and method are disclosed for making a laser balloon catheter having a diffusing tip for propagating a uniform cylindrical pattern of laser energy. Included in the catheter are an elongated flexible tube with an inflatable balloon connected to the tube and means for inflating and deflating the balloon. A central channel is disposed within the balloon and coupled to the tube. An optical fiber with the diffusing tip at its distal end delivers laser radiation through the balloon to tissue to be treated. The method comprises the steps of etching the distal end of the optical fiber to form an etched portion thereof, cladding the etched portion with a medium which secures the optical fiber to the central channel, and microballoons which diffuse the laser radiation radially from the optical fiber, thereby substantially avoiding axial propagation and heating of blood forward of the optical fiber.”
U.S. Pat. No. 5,337,381 for a fiber optic cylindrical diffuser, by Biswas et al, patented Aug. 9, 1994, provides the following description: “A fiber optic, cylindrical, light diffuser for medical use includes an unclad distal fiber end where the exposed core end has a conical shape. The core end is enclosed by a sleeve which contacts the clad portion of the fiber only and defines a closed chamber with the distal end of the fiber. The chamber is filled with light diffusing material. The diffuser exhibits highly uniform output light distribution and is capable of carrying relatively high power densities safely.”
U.S. Pat. No. 5,207,669 for an optical fiber diffusion tip for uniform illumination, by Baker et al, patented May 4, 1993, provides the following description: “A diffusion tip coupled to the end of an optical fiber for directing laser energy outwardly in a cylindrical or other desired radiation pattern. The diffusion tip includes a core, a cladding around the core and a jacket around the cladding. The cladding has an index of refraction that is lower than that of the core and has a thickness selected to transmit a portion of the laser radiation that is carried through the optical fiber so that laser radiation penetrates through the cladding and the jacket over the length of the diffusion tip. The thickness of the cladding is about the same as or slightly less than the penetration depth of the evanescent field in the cladding. The cladding can be tapered along the length of the diffusion tip to provide a uniform radiation pattern. The diffusion tip is particularly useful in a laser balloon catheter utilized in coronary angioplasty.”
U.S. Pat. No. 5,151,096 for a laser catheter diffuser, by Adib I. Khoury, patented Sep. 29, 1992, provides the following description: “A light transmitting and diffusing apparatus is disclosed for activating photodynamic therapy in soft cancerous tumors. In the preferred embodiment, the apparatus is affixed to a standard medical laser that transmits light through an optical fiber to a point adjacent to or within a cancerous tumor. The apparatus includes an unclad fiber-optic core with a reflective cap at a terminal end of the core. A diffuser matrix coats the unclad fiber-optic core and a transparent tubular sleeve encases the matrix and core. The transparent tubular sleeve includes a conical tip adjacent to the terminal end of the core for easy penetration of the cancerous tumors. In use, light leaves the medical laser, travels along the optical fiber into the unclad fiber-optic core. There, some light passes directly out of the core through the diffuser matrix, and the remaining light is reflected, by this reflective cap, back into and around the core, away from its terminal end. The resulting pattern of diffuse light is roughly shaped like a ‘butternut-squash,’ producing a decreased risk of damage to blood vessels, nerves, etc., that may be just beyond the terminal end of the core, along its longitudinal axis.”